Don't change the UUID of the pristine repository.

* subversion/tests/cmdline/update_tests.py
  (update_uuid_changed):
    Call sbox.build() with read_only=False, because otherwise repo_dir
    (which is passed to 'svnadmin setuuid') would point to the pristine
    repository.

git-svn-id: https://svn.apache.org/repos/asf/subversion/trunk@873150 13f79535-47bb-0310-9956-ffa450edef68
diff --git a/subversion/tests/cmdline/update_tests.py b/subversion/tests/cmdline/update_tests.py
index 68cdd5c..7923271 100755
--- a/subversion/tests/cmdline/update_tests.py
+++ b/subversion/tests/cmdline/update_tests.py
@@ -3818,7 +3818,10 @@
     # No 'Repository UUID' line in 'svn info'?
     raise svntest.verify.SVNUnexpectedStdout(output)
 
-  sbox.build(read_only = True)
+  # read_only=False, since we don't want to run setuuid on the (shared)
+  # pristine repository.
+  sbox.build(read_only = False) 
+
   wc_dir = sbox.wc_dir
   repo_dir = sbox.repo_dir